The high cost of automobiles and their high mobility make them prime targets for theft. Most prior anti-theft devices involve the locking of a mechanism critical to the operation of the automobile, such as the ignition system, the steering wheel, the drive shaft, the transmission, etc. Most of those prior systems have the disadvantage of being easily by-passed or defeated, For example, ignition locking systems that do not protect the distributor can be electrically by-passed or "jumped". Nearly all devices which operate by locking a mechanical part may be defeated by "picking" or breaking the lock.
Only a few of the previously proposed anti-theft arrangements have the distributor within the locking system. For example the arrangements described in U.S. Pat. No. 2,136,673 and No. 3,773,138 include protection of the distributor. Such arrangements have an advantage over previous systems in that one can by-pass them only by a rather sophisticated method of substituting a new distributor (along with ignition system adjuncts), which requires time consuming and difficult mechanical modifications and adjustments. The arrangements of the cited patents however, are not without disadvantages, as an analysis of those arrangements will show.
The arrangement described in U.S. Pat. No. 3,773,138 is a locked enclosure attached to the vehicle fire wall within the passenger compartment which contains all the ignition elements including the distributor. That arrangement requires a lengthy driving rod to connect the distributor with a driving means on the engine. That arrangement has the disadvantage that it is difficult to connect the driving rod to the driving means in the standard automobile because the usual placement of the driving means requires that the driving rod exit from the top of the engine; thus in order for the driving rod to enter the passenger compartment one or more right angle turns in the driving rod is necessary. Furthermore the device can be by-passed by the above mentioned substitutional method.
The anti-theft arrangement described in U.S. Pat. No. 2,136,673 employs a means for engaging and disengaging the distributor drive rod through a lockable shaft and lever system. That system has the disadvantage of being easily defeated by breaking the locks, cutting through the sheeting around the flexible shaft, or if a person were familiar with the locking device, by drilling through the casing and disengaging or breaking a single spring within it which releases the lever switch, re-engaging the distributor drive shaft.